Real-time observation of graphene layer growth: Coupling of the interlayer spacing with thickness

In-situ two-dimensional grazing incidence X-ray diffraction was applied in isothermal growth of graphene on nickel through chemical vapor deposition. The analyses showed that the graphene interlayer spacing decreases with the increasing number of graphene layers (growth time increase). Moreover, the as-deposited graphene can be gradually removed through in-situ Ar annealing treatment and inverse interlayer spacing change was also observed, i.e., the interlayer spacing of graphene increases with the number of graphene layers decrease. These results prove that there is a strong coupling effect between the interlayer spacing and the number of graphene layers. The weak interlayer interactions between graphene layers and the interface effects may contribute to this phenomenon. (C) 2015 Elsevier Ltd. All rights reserved.